Seasat
From The Space Library
Seasat was the world's first oceanography satellite equipped with synthetic aperture radar (SAR). It was launched in 1978 and its mission was cut short due to an electrical fault in the rotation assembly of the solar panels. Seasat's bus was a customised Agena stage. Seasat's mission lasted just over 100 days but it provided proof of concept that synthetic aperture radar could be successfully deployed in space for prolonged periods. It was predated by a secret military SAR satellite named Quill which was launched in 1964 but was only functional for a few days.
1977 Seasat Promotional Document (NASA)
1977 Seasat Global Ocean Monitoring System (NASA Technical Report)